1. Field of the Invention
This invention relates to a slide fastener chain for shielding the electromagnetic wave to be used as in connecting shielding means capable of intercepting such electromagnetic waves as disturbing waves and leaky waves and a method for the production thereof.
2. Description of the Prior Art
For the purpose of protecting household electric appliances, electric devices such as electric precision measuring instruments and high frequency-applied devices, and electric wires and cables against troubles caused by disturbing waves or for the purpose of preventing the leaking out of high-frequency waves generated by such instruments, the practice of enclosing such electric devices in shield cages made of metallic nets and other materials which intercept electromagnetic waves or the practice of wrapping the electric wires and cables in covers made of materials capable of shielding electromagnetic waves is in vogue. In recent years, the troubles caused by electromagnetic waves generated as by office-automating (OA) devices have come to raise a problem. For the purpose of precluding this problem, efforts are continued to develop rooms for shielding such OA devices from electromagnetic waves.
For the purpose of facilitating the opening and closing of such shield cages and shield rooms or the attachment and detachment of shield covers, slide fasteners are used to advantage. The slide fasteners which are used in connecting such shielding means against electromagnetic waves are desired to possess a function of shielding themselves from electromagnetic waves.
As a slide fastener which, though not intended directly for the connection of such shielding means, is capable of shielding itself from electromagnetic waves, Japanese Patent Publication No. SHO 56(1981)-32,921, for example, discloses a slide fastener which has fastener elements attached to a fastener tape made of metallic fibers. This slide fastener is intended to exhibit an improved behavior in corrosion resistance, weathering resistance, durability, mechanical strength, etc. by the using in the fastener tape thereof metallic fibers in the place of heretofore used synthetic fibers or natural fibers. The slide fastener which employs the fastener tape made of metallic fibers as described above, however, suffers from inferior flexibility and high cost. Further, the fact that the strength of attachment of the fastener element is insufficient entails the disadvantage that the element is not stabilized in its attached position and it is not easily attached with a fixed pitch. Japanese Utility Model Publication No. SHO 48(1973)-40,084 discloses a tape for use in a slide fastener, which tape comprises a woven fabric formed by using asbestos fibers and glass fibers respectively as warp and weft, an aluminum coating applied to the surface of the woven fabric by vacuum deposition, and a non-flammable core thread or string formed along the lateral edge of the woven fabric. This tape is intended to be used in slide fasteners for binding to the edges of an opening in fireproof garments or fireproof bags. It pays no respect to the shielding of the slide fastener from electromagnetic waves. Further, since the tape uses a woven fabric formed of nonflammable and nonstretchable inorganic fibers and an aluminum coating layer formed for tightly filling gaps in the texture of the fabric and covering the surface of the fabric, it has the disadvantage that it is deficient in flexibility and strentchability and expensive to manufacture.
A slide fastener chain which is intended solely for use in connecting parts of shielding means against electromagnetic waves is disclosed in Japanese Utility Model Application laid open to public inspection; KOKAI No. SHO 58(1983)-164,290. The slide fastener chain disclosed in the specification is produced by forming a folded part at one end of a shielding means against electromagnetic waves, forming a core string part by placing a flexible core member inside the folded part, and binding electroductive fastener elements to the core string part as electrically connected to the shielding means. The slide fastener chain, therefore, is produced as attached to the shielding means. Since this slide fastener chain requires the core string part to be formed inside the folded part of the shielding means such as of a metallic net obtained by warp knitting a thin wire and binding the fastener elements to the core string part, however, it has the disadvantage that the attachment is troublesome and the flexibility is insufficient.